CN112352142B - Method and device for measuring temperature - Google Patents

Abstract

Apparatus and methods for measuring a temperature of a substrate are provided. In one or more embodiments, an apparatus for estimating temperature is provided and includes: a plurality of electromagnetic radiation sources positioned to emit electromagnetic radiation toward the reflective plane; and a plurality of electromagnetic radiation detectors. Each electromagnetic radiation detector is positioned to sample electromagnetic radiation emitted by a corresponding electromagnetic radiation source of the plurality of electromagnetic radiation sources. The apparatus also includes a pyrometer positioned to receive electromagnetic radiation emitted by the plurality of sources of electromagnetic radiation and reflected from a substrate disposed at the reflective plane and electromagnetic radiation emitted by the substrate. The apparatus includes a processor configured to estimate a substrate temperature based on electromagnetic radiation emitted by the substrate. Methods of estimating temperature are also provided.

Description

Method and device for measuring temperature

Technical Field

Aspects of the present disclosure generally relate to methods and apparatus for measuring temperature. Further, aspects of the present disclosure relate to non-contact temperature measurement for a processing chamber.

Background technique

During processing associated with the manufacture of semiconductor devices and the like, numerous thermal processing operations are performed on substrates. Thermal processing generally uses temperature measurements for process control. Inaccurate temperature measurements can lead to poor process results, which can adversely affect semiconductor device performance and/or manufacturing yield.

Optical pyrometers are sometimes used to measure substrate temperature in semiconductor device manufacturing processes. The intensity of electromagnetic radiation emitted from the substrate surface is measured by the optical pyrometer sensor and related to the temperature using Planck's law to determine the substrate temperature. In a typical thermal processing chamber, the optical pyrometer is exposed to electromagnetic radiation from many sources, such as lamps and hot surfaces inside the chamber, while shielding the electromagnetic radiation emitted by the substrate. Interference from electromagnetic noise in the chamber can make it difficult to determine the true substrate temperature, which can lead to erroneous temperature determinations and cause poor processing results.

Therefore, there is a need for improved apparatus and methods for substrate temperature measurement.

Summary of the invention

An apparatus and method for measuring substrate temperature is provided. In one or more embodiments, an apparatus for estimating temperature includes: a plurality of electromagnetic radiation sources positioned to emit electromagnetic radiation toward a reflective plane; and a plurality of electromagnetic radiation detectors, each electromagnetic radiation detector positioned to sample electromagnetic radiation emitted by a corresponding electromagnetic radiation source of the plurality of electromagnetic radiation sources. The apparatus also includes a pyrometer positioned to receive electromagnetic radiation originating from the plurality of electromagnetic radiation sources and reflected from the reflective plane; and a processor configured to estimate temperature based on electromagnetic radiation received by the pyrometer and by the electromagnetic radiation detector.

In other embodiments, a method for estimating temperature includes the steps of: emitting electromagnetic radiation from each of a plurality of electromagnetic radiation sources toward a substrate; and sampling electromagnetic radiation emitted by a corresponding electromagnetic radiation source of the plurality of electromagnetic radiation sources by each of a plurality of electromagnetic radiation detectors. The method also includes the steps of: receiving, by a pyrometer, electromagnetic radiation reflected from the substrate and electromagnetic radiation emitted by the substrate; and using a processor to estimate the temperature of the substrate based on the electromagnetic radiation emitted by the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-described features of the present disclosure may be understood in detail, a more particular description of the present disclosure may be had by reference to embodiments (briefly summarized above), some of which are illustrated in the accompanying drawings. Note, however, that the accompanying drawings illustrate only typical embodiments of the present disclosure and are therefore not intended to limit its scope, as the present disclosure may admit to other equally effective embodiments.

FIG. 1 depicts a simplified schematic diagram of a temperature measurement system according to one aspect of the present disclosure.

2A , 2B, and 2C illustrate examples of pulse train signals according to one aspect of the present disclosure.

3A , 3B and 3C illustrate other examples of pulse train signals according to one aspect of the present disclosure.

4 illustrates a schematic cross-section of a processing chamber into which the temperature measurement system of FIG. 1 is incorporated, according to aspects of the present disclosure.

5 is a flow chart of an exemplary method for detecting an endpoint of an aging process according to aspects of the present disclosure.

It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation. Note, however, that the appended drawings illustrate only exemplary embodiments of the disclosure and are therefore not to be considered limiting of its scope, as the disclosure may admit to other equally effective embodiments.

Detailed ways

In one or more embodiments, an apparatus for estimating temperature is provided. The apparatus includes: a plurality of electromagnetic radiation sources, the plurality of electromagnetic radiation sources are positioned to emit electromagnetic radiation toward a reflecting plane; and a plurality of electromagnetic radiation detectors. Each electromagnetic radiation detector is positioned to sample electromagnetic radiation emitted by a corresponding electromagnetic radiation source of the plurality of electromagnetic radiation sources. The apparatus also includes a pyrometer, the pyrometer is positioned to receive electromagnetic radiation emitted from the plurality of electromagnetic radiation sources and reflected from a substrate disposed at the reflecting plane and electromagnetic radiation emitted by the substrate. The apparatus includes a processor, the processor being configured to estimate the substrate temperature based on the electromagnetic radiation emitted by the substrate. A method for estimating temperature is also provided. FIG. 1 is a simplified schematic diagram of a temperature measurement system 100 according to one aspect of the present disclosure. The temperature measurement system 100 includes electromagnetic radiation sources 102 and 106, electromagnetic radiation detectors 103 and 108, a pyrometer 110, and a controller 120 positioned adjacent to a substrate 101.

The substrate 101 may be a wafer or a panel substrate capable of having materials deposited thereon. In one or more examples, the substrate 101 may be silicon (doped or undoped), crystalline silicon, silicon oxide, doped or undoped polysilicon, etc., a germanium substrate, a silicon germanium (SiGe) substrate, a III-V compound substrate, such as a gallium arsenide substrate, a silicon carbide (SiC) substrate, a patterned or unpatterned semiconductor on insulator (SOI) substrate, a carbon-doped oxide, silicon nitride, a solar array, a solar panel, a light emitting diode (LED) substrate, or any other material such as metal, metal alloy, and other conductive materials. In some examples, the substrate 101 may be a substrate holder or substrate base, a suction seat plate, etc. The substrate 101 may also include multiple layers, such as a semi-insulating material and a semi-conductive material, wherein the semi-insulating material has a higher resistivity than the semi-conductive material. The substrate 101 is not limited to any particular size and shape. According to the resistivity of the substrate material near the surface of the substrate 101, the substrate 101 reflects incident electromagnetic radiation having a wavelength of about 50 μm to about 100 cm.

The temperature measurement system 100 also includes signal generators 104 and 107. The signal generators 104 and 107 apply time-varying power to the electromagnetic radiation sources 102 and 106, respectively. In one or more embodiments, each signal generator 104, 107 may generate a variety of waveforms having different periodicities, shapes (e.g., sinusoidal pulses or triangular pulses), patterns, and/or amplitudes. In some cases, the signal generators 104 and 107 may send power pulses to the electromagnetic radiation sources 102 and 106. The use of the signal generators 104 and 107 allows short pulses of electromagnetic radiation to be emitted from the electromagnetic radiation sources 102 and 106 to determine the reflectivity from the substrate 101.

The electromagnetic radiation source 102 emits electromagnetic radiation L ₁ with a time-varying intensity toward the substrate 101 according to the signal provided by the signal generator 104. The electromagnetic radiation source 106 emits electromagnetic radiation L ₂ with a time-varying intensity toward the substrate 101 according to the signal provided by the signal generator 107. In one or more embodiments, each of the electromagnetic radiation sources 102 and 106 may be a heat source (e.g., a heating lamp) to provide thermal energy to the substrate 101 for increasing the temperature of the substrate 101.

The electromagnetic radiation detector 103 has a probe head 141 disposed adjacent to the electromagnetic radiation source 102 and detects electromagnetic radiation L ₃ from a portion of the emission cone 131 of _the electromagnetic radiation source 102. The electromagnetic radiation L ₃ corresponds to the electromagnetic radiation L 1 reflected from the substrate 101 and detected by the pyrometer 110 as electromagnetic radiation R _1. The probe head 141 of the detector 103 is disposed in a line-of-sight to the emission element 142 of the electromagnetic radiation source 102. The electromagnetic radiation in the emission cone 131 has substantially the same intensity at all emission angles within the emission cone 131. In one or more embodiments, the probe head 141 of the detector 103 is aligned with a conical surface of the emission cone 131 of the electromagnetic radiation source 102. In one or more embodiments, the detector 103 is coupled to a sampling circuit 105 to determine a sampling rate of the detector 103.

The detector 108 is disposed in a line of sight to an emission element 144 of an electromagnetic radiation source 106. The electromagnetic radiation source 106 includes a light emitting element 144 disposed within a reflector 146. The detector 108 includes a probe head 143 disposed adjacent to the source 106 and detects electromagnetic radiation L ₄ from an emission cone 132 of the source 106 corresponding to electromagnetic radiation L _2. In one or more embodiments, the probe head 143 of the detector 108 is aligned with a conical surface of the emission cone 132 of the electromagnetic radiation source 106. In one or more embodiments, the detector 108 is coupled to a sampling circuit 109 to determine a sampling rate of the detector 108. The temperature measurement system 100 can achieve higher temperature resolution at a higher sampling rate.

In one or more embodiments, the detectors 103 and 106 are made of optical fibers. In other embodiments, the detectors 103 and 106 include probe heads 141, 143 bent at respective angles to align with the radiation beams _L3 and _L4 , respectively. In other embodiments, an opening 102a is formed in a reflector 145 in the electromagnetic radiation source 102. The opening 102a is disposed in a position to pass electromagnetic radiation _L5 through the opening 102a to a detector, such as the detector 103, which is positioned to receive the electromagnetic radiation _L5 through the opening 102a. Although not shown, the electromagnetic radiation source 106 may also include an opening similar to the opening 102a.

The emitting elements 142, 144 of the respective electromagnetic radiation sources 102 and 106 emit electromagnetic radiation having generally similar intensities in all directions. Therefore, electromagnetic radiation _L3 has substantially the same intensity as the corresponding electromagnetic radiation _L1 . Similarly, electromagnetic radiation _L4 has substantially the same intensity as electromagnetic radiation _L2 . In operation, the controller 120 estimates the intensity of electromagnetic radiation _L1 from the intensity of the corresponding electromagnetic radiation _L3 . The controller 120 also estimates the intensity of electromagnetic radiation _L2 from the intensity of the corresponding electromagnetic radiation _L4 .

The pyrometer 110 detects electromagnetic radiation emitted and/or reflected from the substrate 101. The electromagnetic radiation received at the pyrometer 110 includes electromagnetic radiation _T1 emitted from the substrate 101, and electromagnetic radiation reflected from the substrate 101, such as _L1 and _L2 . In one or more embodiments, the pyrometer 110 includes an optical narrowband filter having a bandpass of about 20 nm at wavelengths less than 950 nm, i.e., photon energies above the silicon bandgap of about 1.1 eV (about 1.1 μm). The bandpass may alternatively be expressed as a photon wavelength below the bandgap wavelength of the substrate 101. Using a pyrometer with narrowband functionality reduces noise from other sources in other spectral bands, thereby improving measurement accuracy.

In some embodiments, the electromagnetic radiation sources 102 and 106 may be operated at different wavelengths. In this embodiment, the pyrometer 110 includes detection elements for different wavelengths to spectrally separate the radiation from the individual electromagnetic radiation sources. In such a case, the temperature measurement system 100 may determine the reflectivity of the substrate 101 while operating the electromagnetic radiation sources. In such an example, the electromagnetic radiation sources 102 and 106 are configured to emit a spectrum of radiation having multiple wavelengths (e.g., from infrared light to ultraviolet light). In one or more embodiments, a fast Fourier transform (FFT) analyzer 111 is coupled to the pyrometer 110 to separate the reflected radiation received by the pyrometer 110 according to wavelength. In some embodiments, a lock-in amplifier may be coupled to the pyrometer 110 to separate the received reflected radiation. In other embodiments, one of the electromagnetic radiation sources 102 and 106 is operated at the same wavelength or at different wavelengths at a time.

The temperature measurement system 100 is connected to a controller 120 to control various aspects of the temperature measurement system 100 during processing. The controller 120 includes a central processing unit (CPU) 121, a memory 122, a storage 124, and support circuits 123 for the CPU 121. The controller 120 facilitates the control of the components of the temperature measurement system 100, and potentially facilitates the control of other components of the device using the temperature measurement system 100. The controller 120 can be a general-purpose computer that can be used in an industrial setting for controlling a variety of chambers and sub-processors. The memory 122 stores software (source or object code) that can be executed or called to control the overall operation of the temperature measurement system 100 in the manner described herein. The controller 120 manipulates the individual operations of the controllable components in the temperature measurement system 100. The controller 120 may include power supplies for the components of the temperature measurement system 100.

The controller 120 is coupled to the plurality of signal generators 104 and 107 and controls the signals from the respective signal generators 104 and 107 to be applied to the electromagnetic radiation sources 102 and 106. The controller 105 also receives radiation data from the pyrometer 110 and/or circuitry corresponding to the pyrometer 110 (e.g., FFT analyzer (or lock-in amplifier) 111). The controller 105 processes the radiation data received by the pyrometer 110 to estimate the temperature of the substrate 101, as described below.

In FIG. 1 , electromagnetic radiation sources 102 and 106, detectors 103 and 108, and pyrometer 110 are illustrated as being located below substrate 101. However, these components may be located at any convenient location, such as a location above substrate 101, or to a side of substrate 101 when substrate 101 is oriented vertically. Any number of sources 102, 106 and detectors 103, 108 may also be used. Further, more than one pyrometer 110 may be used to measure the temperature at multiple locations or within different regions of substrate 101. Multiple sources, detectors, and pyrometers can improve the signal-to-noise ratio.

During operation of monitoring the temperature of substrate 101, signal generators 104 and 107 input time-varying signals into electromagnetic radiation sources 102 and 106. Electromagnetic radiation sources 102 and 106 receive the time-varying signals and transmit electromagnetic radiation _L1 and _L2 toward substrate 101, respectively, based on the input time-varying signals. Radiation _L1 strikes substrate 101 at an incident angle _θ1 and is partially absorbed, partially transmitted, and/or partially reflected. Similarly, radiation _L2 strikes substrate 101 at an incident angle _θ2 and is partially absorbed, partially transmitted, and/or partially reflected. Reflected radiation _R1 and _R2 continue toward pyrometer 110.

Detectors 103 and 108 detect radiation _L3 and _L4 , corresponding to radiation _L1 and _L2 , respectively. Radiation _L3 has substantially the same intensity as corresponding radiation _L1 , or the intensities of the two radiation components have a defined relationship, so the intensity of radiation _L3 (measured by detector 103) can be used to determine the intensity of radiation _L1 . Radiation _L4 and radiation _L2 share a similar relationship, facilitating the use of detector 108 to determine radiation _L2 .

The pyrometer 110 detects the total intensity of electromagnetic radiation, i.e., the total intensity of the combined radiations T ₁ , R ₁ , and R _2. Therefore, the intensity of the combined electromagnetic radiation (denoted as _{I_SP} ) detected by the pyrometer 110 is the intensity of the radiation T ₁ I_T ₁ plus the intensity of the radiation R ₁ I_R ₁ plus the intensity of the radiation R ₂ I_R _2. Therefore, the intensity of the combined electromagnetic radiation _{I_SP} is expressed as:

_{I_SP} ＝ _{I_T1} + _{I_R1} + _{I_R2} (1)

The reflectivity ρ of the substrate 101 is defined as the ratio of the intensity of the reflected beam (eg, R ₁ ) to the incident beam (eg, L ₁ ). Therefore, the reflectivity ρ of the substrate 101 is expressed as:

Here, _ΔL1 is the maximum intensity of radiation _L1 (e.g., peak 201 of FIG. 2A ) minus the minimum intensity of radiation _L1 (e.g., 202 of FIG. 2A ). Similarly, _ΔR1 is the maximum intensity of reflected radiation _R1 minus the minimum intensity of reflected radiation _R1 . Similarly, _ΔL2 is the maximum intensity of radiation _L2 (e.g., 211 of FIG. 2B ) minus the minimum intensity of radiation _L2 (e.g., 212 of FIG. 2B ). Similarly, _ΔR2 is the maximum intensity of reflected radiation _R2 minus the minimum intensity of reflected radiation _R2 .

In one or more embodiments, to determine the reflectivity p, the temperature measurement system 100 may activate only one of the electromagnetic radiation sources 102 , 106 to emit electromagnetic radiation and measure the reflected radiation. The reflectivity p depends on the temperature of the substrate 101 , facilitating determination of the temperature of the substrate 101 .

The intensity of the emitted radiation T ₁ (I_T ₁ ) is expressed by the following equation:

I_T ₁ = I_SP - _{I_R 1} - I_R ₂ = _{I_SP} - ρxI_L _{1 -} ρxI_L ₂ (3)

As described above, each of electromagnetic radiations _L1 and _L2 has substantially the same intensity ( _{I_L1} , _{I_L2} ) as corresponding electromagnetic radiations _L3 and _L4 ( _{I_L3} , _{I_L4} ), respectively (sampled and measured by electromagnetic radiation detectors 103, 108, respectively). Therefore, due to this equivalence, Equation 3 can be rewritten as:

I_T ₁ = I_SP - _{I_R 1} - I_R ₂ = I_SP _- ρxI_L ₃ - ρxI_L ₄ (4)

The absolute temperature T of the sample is calculated by applying Planck's law (maintaining that the emitted radiation T ₁ =B _v (v, T)) given the spectral radiation of frequency v from the body at absolute temperature T as:

Here k _B is the Boltzmann constant, h is the Planck constant, and c is the speed of light in a medium (whether a material or a vacuum), and T is the absolute temperature of the substrate 101. Planck's law is generally regulated by the emissivity of the object, which is defined according to Planck's law as the ratio of the actual thermal radiation output to the theoretical output. Therefore, Planck's law can be used to estimate the temperature of an object, such as the substrate 101.

The above series of equations describe how to estimate the temperature of substrate 101 based on two radiation samples. However, these equations can be extended to any embodiment where the pyrometer receives a varying number of radiation samples, as will be discussed further below.

2A, 2B, and 2C illustrate examples of pulse train signals according to one aspect of the present disclosure. Examples of time-varying power signals are illustrated in FIGS. 2A and 2B. A time-varying power signal (e.g., a pulse signal) may be used to measure the reflectivity of a substrate, such as substrate 101 shown in FIG. 1, during a calibration process performed with each new substrate. When a new substrate is introduced into an apparatus having a temperature measurement system herein (described in connection with FIG. 1), each electromagnetic radiation source pulses a plurality of times, such as 10 times, to determine the reflectivity of the substrate. In one or more embodiments, the temperature measurement system may rotate the substrate while the electromagnetic radiation source pulses to prevent reflectivity from varying across the surface of the substrate. In other embodiments, the temperature measurement system may synchronize the pulsing and the rotation so that the system uses different detectors 103 and 108 to double sample the reflectivity.

FIG2A illustrates a signal 200 to be applied to electromagnetic radiation source 102, which then emits electromagnetic radiation _L1 having a time-varying intensity in accordance with signal 200. FIG2B illustrates a signal 210 to be applied to electromagnetic radiation source 106, which then emits electromagnetic radiation _L2 having a time-varying intensity in accordance with signal 210. Signal 200 is a time-varying voltage having a peak 201, with peak 201 having a peak voltage _VL1 during a cycle time _t1 . Signal 210 is a time-varying voltage having two peaks 211, with each peak 211 having a peak voltage _VL2 during a cycle time _t2 . In this embodiment, peaks 201 and 211 do not overlap in time. FIG2C illustrates an exemplary signal 220 received by pyrometer 110 when electromagnetic radiation sources 102 and 106 are operated in accordance with signals 200 and 210, respectively. The pyrometer 110 receives reflected radiation _R1 and _R2 from respective electromagnetic radiation sources 102 and 106, and emitted radiation _T1 from the substrate 101 (due to thermal energy of the substrate 101). The received signal 220 has three pulses, a first pulse 221 corresponding to the peak 201 of the signal 200, and a second pulse 222 and a third pulse 223 corresponding to the peak 211 of the signal 210.

Different examples of time-varying power signals are shown in FIGS. 3A and 3B . FIG. 3A shows a signal 300 to be applied to the electromagnetic radiation source 102, and FIG. 3B shows a signal 310 to be supplied to the electromagnetic radiation source 106. Signal 300 is a time-varying voltage having a peak value 301 (peak value 301 having a peak voltage V _L1 in a cycle time t ₁ ). Signal 310 is a time-varying voltage having two peak values 311, 312 (each having a peak voltage V _L2 in a cycle time t ₂ ). Here, one peak value 301 overlaps with the peak value 311 in time.

3C illustrates an exemplary signal 320 received by the pyrometer 110 when the electromagnetic radiation sources 102 and 106 are operated according to the signals 300 and 310, respectively. The received signal 320 has two pulses, a first pulse 321 corresponding to the overlapping peaks 301 and 311, and a second pulse 322 corresponding to the peak 312. The first pulse 321 is generated by reflected electromagnetic radiation from both electromagnetic radiation sources 102 and 106 that are simultaneously received by the pyrometer 110.

Referring again to FIG. 1 , electromagnetic radiation sources 102 and 106 emit electromagnetic radiation at all azimuth angles in respective emission cones 131 and 132 toward substrate 101. The electromagnetic radiation strikes substrate 101 and is partially absorbed, partially transmitted, and partially reflected by varying amounts in corresponding reflection cones at different wavelengths. Electromagnetic radiation reflected at a range of reflection angles continues toward pyrometer 110 and can be detected by pyrometer 110. For example, using a ray tracing approach for clarity, radiation _L1 and _L2 emitted from electromagnetic radiation sources 102 and 106 in respective emission cones 131 and 132 is incident at substrate 101 at angles of incidence _θ1 and _θ2 , respectively, and is partially reflected at substrate 101. Reflected radiation _R1 and _R2 continues toward and is detected by pyrometer 110 at reflection area 133, as illustrated in FIG. 1 . The reflection area 133 sampled by the pyrometer 110 contains a portion of the band of radiation reflected by the substrate 101 from each emission cone 131 and 132 defined by the azimuth seen by the pyrometer 110. The reflected radiation is detected by the pyrometer 110 at the azimuth seen by the pyrometer 110 when the angles of incidence _θ1 and _θ2 are within a particular range.

4 illustrates a schematic cross-section of a processing chamber 400 incorporating the temperature measurement system 100 of FIG 1. The processing chamber 400 features an enclosure 402, a substrate support 404 disposed in the enclosure 402, a process module 403 coupled to the enclosure 402, a plurality of electromagnetic radiation sources 405 (405-1, 405-2, 405-3, 405-4, 405-5, and 405-6), and a signal generator 407 (407-1, 407-2, 407-3, 407-4, 407-5, and 407-6) coupled to the plurality of sources 405, a plurality of detectors 406 (406-1, 406-2, 406-3, 406-4, 406-5, and 406-6), and a pyrometer 408.

The processing module 403 includes one or more conduits 411 (two are shown) for introducing materials into the enclosure 402. The conduits 411 can be used to guide gases or liquids, and can be straight, as shown in Figure 4, or tortuous to any desired degree. Two conduits 411 are shown in Figure 4, but any number can be used. For example, the processing module 403 can include a showerhead, which can have multiple zones or passages. The processing module 403 can be coupled to any desired delivery device, such as a gas box, vaporizer, ampoule, etc., through suitable conduits.

The substrate support 404 is heated by heating lamps embedded in the substrate support 404. The substrate support 404 may also be electrified, for example using a biasing element, to provide electrostatic fixation of the substrate 401 on the substrate support 404. A rotation drive (not shown) may be coupled to the substrate support 404 to provide rotational motion during processing, between processing cycles, or both. In embodiments where the substrate 401 is rotated during processing, the substrate 401 may be probed at selected intervals to monitor the temperature of different locations on the substrate 401 so that temperature uniformity may be controlled.

Each signal generator 407-1 to 407-6 is coupled to a respective electromagnetic radiation source 405. Each of the signal generators 407-1 to 407-6 generates a time-varying signal and applies the time-varying signal to a respective electromagnetic radiation source 405. The electromagnetic radiation sources 405-1 to 405-6 emit electromagnetic radiation _L1 to _L6 toward the substrate 401. The plurality of electromagnetic radiation sources 405-1 to 405-6 may be heat sources for providing thermal energy to the substrate 401.

Each detector 406-1 to 406-6 is disposed adjacent to a respective electromagnetic radiation source 405-1 to 405-6 to detect electromagnetic radiation _L1a to _L6a corresponding to electromagnetic radiation _L1 to L6 that is partially reflected at substrate 401 and received by pyrometer 408. A portion of each electromagnetic radiation detector 406-1 to 406-6 is placed in a line of sight to a transmitting element of the respective electromagnetic radiation source 405-1 to 405-6. Electromagnetic radiation detectors 406-1 to 406-6 include support circuitry to sample radiation beams _L1a to _L6a at respective sampling rates _.

The processing chamber 400 may include any number of sources 405 , each source 405 having a corresponding signal generator 407 and electromagnetic radiation detector 406 .

The pyrometer 408 detects electromagnetic radiation propagating from the substrate 401 toward the pyrometer 408. The radiation detected by the pyrometer 408 includes radiation _T1 emitted from the substrate 404 and reflected radiation _R1 - _R6 .

In operation, the processing chamber 400 estimates the temperature of the substrate 401 in a manner similar to that described above with respect to FIG. 1. Here, the processing chamber 400 includes six (6) electromagnetic radiation sources 405-1 through 405-6 and detectors 406-1 through 406-6, but any number of sources and detectors may be used. In such an embodiment, the pyrometer 408 returns a radiation intensity _{I_SP} from any number of electromagnetic radiation sources and emitted electromagnetic radiation _T1 reflected from the substrate 401 as follows:

Based on the definition of reflectivity ρ (which can be determined as described above in connection with FIGS. 2A to 3C ), Equation 6 can be rewritten as:

Each electromagnetic radiation _L1 , _L2 , _L3 , ... _Ln has substantially the same intensity as the corresponding electromagnetic radiation _L1a , _L2a , _L3a , ... _Lna (sampled by the electromagnetic radiation detector 406). Therefore, Equation 7 can be rewritten as:

Next, based on the determined reflectivity ρ and the incident electromagnetic radiation I_L _ia detected by the detector 406 , the intensity of the reflected radiation _is subtracted from the intensity of the total radiation returned by the pyrometer 408 . The intensity I_T ₁ of the emitted electromagnetic radiation is calculated. Next, the temperature of the substrate 401 is estimated by applying Planck's law to the intensity I_T ₁ of the emitted electromagnetic radiation T ₁ , as described in connection with FIG. 1 .

4 shows the electromagnetic radiation source, detector, and pyrometer mounted below the substrate 401. However, these components may be disposed at any convenient location in the processing chamber 400, such as above the substrate 401.

The processing chamber 400 may be a chemical vapor deposition (CVD) chamber, such as a plasma enhanced CVD chamber, a high density plasma CVD chamber, a low pressure CVD chamber, a reduced pressure CVD chamber, or an atmospheric pressure CVD chamber. In other embodiments, the processing chamber 400 may also be a PVD chamber, an etch chamber (thermal or plasma), an epitaxy chamber, an annealing chamber, or any other processing chamber where temperature monitoring may be useful. Examples of the processing chamber 400 may include a CVD chamber such as the VIZO-1000 commercially available from Applied Materials Inc., Santa Clara, California. PECVD chamber, PRODUCER ^TM chamber, and PRECISION /> Chamber.

Controller 420 may be substantially the same as the controller of FIG1 . Controller 420 may be coupled to pyrometer 408 and its associated circuitry to monitor data received by pyrometer 408 and process the data to estimate the temperature of substrate 401 .

In one or more embodiments, the processing chamber 400 may include a plurality of pyrometers 408 to detect the temperature at multiple locations of the substrate 401. By using temperature indications from the plurality of pyrometers 408, temperature non-uniformity of the substrate 401 may be detected and temperature uniformity of the substrate 401 may be improved.

In other embodiments, multiple substrates may be disposed on the substrate support 404 for simultaneous processing in the processing chamber 400, and multiple pyrometers may be provided with one or more pyrometers corresponding to each substrate.

FIG. 5 is a flow chart 500 of an exemplary method for estimating substrate temperature according to aspects of the present disclosure.

In operation 502, a signal generator is used to generate a pulse signal of time-varying power to an electromagnetic radiation source. The signal generator can generate a variety of waveforms with different periodicities, pulse shapes (e.g., sinusoidal pulses or triangular pulses), pulse patterns, and/or amplitudes. More than one electromagnetic radiation source can be used, each electromagnetic radiation source including a separate signal generator.

In operation 504, the electromagnetic radiation source emits electromagnetic radiation toward the substrate in accordance with the signal from the signal generator. Where multiple electromagnetic radiation sources are used, each source emits in accordance with a signal from a corresponding signal generator.

In operation 506, the detector detects electromagnetic radiation, including radiation emitted by an electromagnetic radiation source. In one or more embodiments, the probe head of each detector is disposed in a line of sight to an emission element of a corresponding electromagnetic radiation source. The emitted electromagnetic radiation has a substantially constant intensity at all angles. In one or more embodiments, the probe head of the detector may be aligned to a conical surface of an emission cone of an electromagnetic radiation source. In the case of using multiple electromagnetic radiation sources, each source has a corresponding detector.

In operation 508, the pyrometer detects the intensity of electromagnetic radiation emitted and/or reflected from the substrate. The electromagnetic radiation received at the pyrometer includes thermal electromagnetic radiation emitted from the substrate, and electromagnetic radiation reflected from the substrate.

In operation 510, the controller determines the intensity of the emitted electromagnetic radiation ( _T1 in FIG. 1) by subtracting the sum of the sampled electromagnetic radiation intensities from the total intensity of the electromagnetic radiation received by the pyrometer to obtain the emitted intensity. The controller further estimates the temperature T of the substrate by applying Planck's law to the determined emitted electromagnetic radiation intensity, as described above.

Embodiments of the present disclosure may further relate to any one or more of the following paragraphs:

1. An apparatus for estimating temperature, comprising: a plurality of electromagnetic radiation sources, the plurality of electromagnetic radiation sources being positioned to emit electromagnetic radiation toward a reflecting plane; a plurality of electromagnetic radiation detectors, each electromagnetic radiation detector being positioned to sample electromagnetic radiation emitted by a corresponding electromagnetic radiation source of the plurality of electromagnetic radiation sources; a pyrometer, the pyrometer being positioned to receive electromagnetic radiation originating from the plurality of electromagnetic radiation sources and reflected from the reflecting plane; and a processor, the processor being configured to estimate temperature based on electromagnetic radiation received by the pyrometer and by the electromagnetic radiation detector.

2. A device for estimating temperature, comprising: a plurality of electromagnetic radiation sources, the plurality of electromagnetic radiation sources are positioned to emit electromagnetic radiation toward a reflecting plane, wherein each electromagnetic radiation source is configured to emit a cone of electromagnetic radiation; a plurality of electromagnetic radiation detectors, each electromagnetic radiation detector is positioned to sample electromagnetic radiation emitted by a corresponding electromagnetic radiation source of the plurality of electromagnetic radiation sources; a pyrometer, the pyrometer is positioned to receive electromagnetic radiation originating from the plurality of electromagnetic radiation sources and reflected from the reflecting plane; and a processor, the processor is configured to estimate temperature based on electromagnetic radiation received by the pyrometer and by the electromagnetic radiation detector.

3. A method for estimating temperature, the method comprising the following steps: each of a plurality of electromagnetic radiation sources emits electromagnetic radiation toward a substrate; each of a plurality of electromagnetic radiation detectors samples the electromagnetic radiation emitted by a corresponding electromagnetic radiation source of the plurality of electromagnetic radiation sources; a pyrometer receives electromagnetic radiation reflected from the substrate and electromagnetic radiation emitted by the substrate; and using a processor to estimate the temperature of the substrate based on the electromagnetic radiation emitted by the substrate.

4. An apparatus or method as described in any of paragraphs 1 to 3, wherein each electromagnetic radiation detector includes a probe head disposed in a line of sight to the emitting element of the corresponding electromagnetic radiation source.

5. An apparatus or method as described in paragraph 4, wherein each electromagnetic radiation source is configured to emit electromagnetic radiation in an emission cone toward the reflective plane, and a portion of the electromagnetic radiation in the emission cone at a first angle is reflected from the reflective plane and then received by the pyrometer.

6. An apparatus or method as described in paragraph 5, wherein the probe head of each electromagnetic radiation detector is curved to align with the conical surface of the emission cone and is configured to sample electromagnetic radiation in the emission cone at a second angle.

7. An apparatus or method as described in paragraph 6, wherein a portion of the electromagnetic radiation in the emission cone at the first angle has substantially the same intensity as another portion of the electromagnetic radiation in the emission cone at the second angle.

8. An apparatus or method as described in any of paragraphs 1 to 7, wherein the processor is configured to receive the intensity of electromagnetic radiation received by the pyrometer and the intensity of electromagnetic radiation sampled by the electromagnetic radiation detector, determine the intensity of radiation reflected from the reflecting plane by the intensity of the electromagnetic radiation sampled by the electromagnetic radiation detector, and estimate the temperature by subtracting the intensity of the reflected radiation from the electromagnetic radiation received by the pyrometer.

9. An apparatus or method as described in paragraph 8, wherein the intensity of reflected radiation from the reflective plane is determined by applying a known reflectivity at the reflective plane to the intensity of electromagnetic radiation sampled by the electromagnetic radiation detector.

10. An apparatus or method as described in paragraph 9, wherein the reflectivity is determined by: calculating a first quantity by subtracting a minimum intensity of the electromagnetic radiation sampled by the electromagnetic radiation detector from a maximum intensity of the electromagnetic radiation sampled by the electromagnetic radiation detector; calculating a second quantity by subtracting a minimum intensity of the electromagnetic radiation detected by the pyrometer from a maximum intensity of the electromagnetic radiation detected by the pyrometer; and calculating a ratio of the first quantity to the second quantity.

11. An apparatus or method as described in any of paragraphs 1 to 10, wherein the temperature is estimated by applying Planck's law to the difference between the intensity of electromagnetic radiation received by the pyrometer and the intensity of electromagnetic radiation reflected from the reflecting plane.

12. The apparatus or method of paragraph 11, wherein each electromagnetic radiation detector comprises a probe head disposed in a line of sight to the emitting element of the corresponding electromagnetic radiation source.

13. An apparatus or method as described in paragraph 12, wherein each electromagnetic radiation source emits electromagnetic radiation in an emission cone toward the substrate, and a portion of the electromagnetic radiation in the emission cone at a first angle is reflected from the reflecting plane and then received by the pyrometer.

14. An apparatus or method as described in paragraph 13, wherein the probe head of each electromagnetic radiation detector is curved to align with the conical surface of the emission cone and is configured to sample electromagnetic radiation in the emission cone at a second angle.

15. An apparatus or method as described in paragraph 14, wherein the electromagnetic radiation in the emission cone at the first angle has substantially the same intensity as the electromagnetic radiation in the emission cone at the second angle.

16. The apparatus or method of paragraph 15, further comprising the step of determining electromagnetic radiation emitted by the substrate by subtracting electromagnetic radiation reflected from the substrate from electromagnetic radiation received by the pyrometer.

17. The apparatus or method of paragraph 16, further comprising the following step: calculating the intensity of the electromagnetic radiation emitted by the substrate by multiplying the intensity of the electromagnetic radiation sampled by each electromagnetic radiation source by the known reflectivity of the substrate, summing the results, and subtracting the sum from the intensity of the electromagnetic radiation received by the pyrometer.

18. The apparatus or method of paragraph 17, wherein the reflectivity of the substrate is the ratio of the intensity of reflected electromagnetic radiation to the intensity of incident electromagnetic radiation.

19. An apparatus or method as described in paragraph 17, wherein the reflectivity of the substrate is calculated by dividing the maximum intensity minus the minimum intensity of the electromagnetic radiation emitted by the electromagnetic radiation source by the maximum intensity minus the minimum intensity of the electromagnetic radiation emitted by the electromagnetic radiation source and reflected from the reflecting plane.

20. The apparatus or method of any of paragraphs 1 to 19, further comprising the step of estimating the temperature of the substrate by applying Planck's law to the electromagnetic radiation emitted by the substrate.

The foregoing description is provided to enable any person of ordinary skill in the art to implement the various embodiments described herein. Various modifications to the embodiments described will be apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other embodiments. For example, changes may be made to the functionality and arrangement of components discussed without departing from the scope of the present disclosure. Various examples may omit, replace, or add suitable various procedures or components. The features associated with some examples may also be combined in some other examples. For example, a device may be implemented or a method may be implemented using any number of aspects proposed herein. In addition, the scope of the present disclosure is intended to cover the device or method implemented using other structures, functionality, or in addition to the various aspects of the present disclosure proposed herein or other structures and functionality. It should be understood that any aspect of the present disclosure disclosed herein may be embodied by one or more elements of the claims.

As used herein, the word “exemplary” means “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects.

As used herein, the term "determine" has a wide range of actions. For example, "determine" may include calculating, computing, processing, obtaining, investigating, searching (e.g., searching in a table, database, or other data structure), ascertaining, etc. "Determine" may also include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory), etc. "Determine" may also include resolving, selecting, deciding, establishing, etc.

The methods disclosed herein include one or more operations or actions for implementing the methods. Method operations and/or actions may be interchangeable with each other without departing from the scope of the claims or the disclosure. In other words, unless a specific order of operations or actions is specified, the order and/or use of specific operations and/or actions may be modified without departing from the scope of the claims.

The following claims are not intended to limit the embodiments shown herein, but are intended to be consistent with the full scope of the language of the claims. Within the claims, reference to an element in the singular is not intended to mean "one and only one" (unless otherwise stated), but rather "one or more". Unless otherwise stated, the term "some" refers to one or more. All structural and functional equivalents of the elements of the various aspects described throughout this disclosure (known or to become known to those of ordinary skill in the art) are expressly incorporated herein by reference and are intended to be owned by the claims. In addition, the content disclosed herein is not intended to be committed to the public, regardless of whether the disclosure is explicitly stated in the claims.

While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure may be modified without departing from the basic scope thereof, and such scope is determined by the claims which follow.

Claims (20)

1. A device for estimating temperature, comprising: a plurality of electromagnetic radiation sources positioned to emit electromagnetic radiation toward a reflective plane; a plurality of electromagnetic radiation detectors, each electromagnetic radiation detector comprising a probe head configured to receive electromagnetic radiation, the probe head being placed at a location between the electromagnetic radiation source and the reflecting plane in order to sample electromagnetic radiation emitted by a corresponding electromagnetic radiation source of the plurality of electromagnetic radiation sources; a pyrometer positioned to receive electromagnetic radiation originating from the plurality of electromagnetic radiation sources and reflected from the reflective plane; and A processor is configured to estimate temperature based on electromagnetic radiation received by the pyrometer and by the electromagnetic radiation detector. 2. The apparatus of claim 1, wherein each probe head is disposed in a line of sight to a transmitting element of the corresponding electromagnetic radiation source. 3. The apparatus of claim 2, wherein each electromagnetic radiation source is configured to emit electromagnetic radiation in an emission cone toward the reflective plane, and a portion of the electromagnetic radiation in the emission cone at a first angle is reflected from the reflective plane and then received by the pyrometer. 4. An apparatus as described in claim 1, wherein the processor is configured to receive the intensity of electromagnetic radiation received by the pyrometer and the intensity of electromagnetic radiation sampled by the electromagnetic radiation detector, determine the intensity of reflected radiation from the reflecting plane by the intensity of the electromagnetic radiation sampled by the electromagnetic radiation detector, and subtract the intensity of the reflected radiation from the electromagnetic radiation received by the pyrometer to estimate the temperature. 5. The apparatus of claim 4, wherein the intensity of reflected radiation from the reflective plane is determined by applying a known reflectivity at the reflective plane to the intensity of electromagnetic radiation sampled by the electromagnetic radiation detector. 6. The apparatus of claim 5, wherein the reflectivity is determined by: calculating a first quantity by subtracting a minimum intensity of electromagnetic radiation sampled by the electromagnetic radiation detector from a maximum intensity of electromagnetic radiation sampled by the electromagnetic radiation detector; calculating a second quantity by subtracting a minimum intensity of electromagnetic radiation detected by the pyrometer from a maximum intensity of electromagnetic radiation detected by the pyrometer; and A ratio of the first amount to the second amount is calculated. 7. The apparatus of claim 1, wherein the temperature is estimated by applying Planck's law to the difference between the intensity of electromagnetic radiation received by the pyrometer and the intensity of electromagnetic radiation reflected from the reflecting plane. 8. An apparatus for estimating temperature, comprising: a plurality of electromagnetic radiation sources, the plurality of electromagnetic radiation sources being arranged to emit electromagnetic radiation in an emission cone toward the reflecting plane; a plurality of electromagnetic radiation detectors, each electromagnetic radiation detector positioned to sample electromagnetic radiation emitted by a corresponding electromagnetic radiation source of the plurality of electromagnetic radiation sources, wherein each electromagnetic radiation detector comprises a probe head that is curved to align with a conical surface of the emission cone and is configured to sample electromagnetic radiation in the emission cone at a second angle; a pyrometer positioned to receive electromagnetic radiation originating from the plurality of electromagnetic radiation sources and reflected from the reflective plane; and a processor configured to estimate temperature based on electromagnetic radiation received by the pyrometer and sampled by the electromagnetic radiation detector; A portion of the electromagnetic radiation in the emission cone at a first angle is reflected from the reflective plane and then received by the pyrometer. 9. The apparatus of claim 8, wherein the portion of electromagnetic radiation in the emission cone at the first angle has substantially the same intensity as another portion of the electromagnetic radiation in the emission cone at the second angle. 10. A method for estimating temperature, the method comprising the steps of: emitting electromagnetic radiation from each of a plurality of electromagnetic radiation sources toward a substrate; sampling electromagnetic radiation emitted by a corresponding electromagnetic radiation source of the plurality of electromagnetic radiation sources by each of a plurality of electromagnetic radiation detectors, each electromagnetic radiation detector comprising a probe head positioned at a location between the electromagnetic radiation source and the substrate; receiving, by a pyrometer, electromagnetic radiation reflected from the substrate and electromagnetic radiation emitted by the substrate; and A processor is used to estimate a temperature of the substrate based on electromagnetic radiation emitted by the substrate. 11. The method of claim 10, wherein each probe head is disposed in a line of sight to a transmitting element of the corresponding electromagnetic radiation source. 12. The method of claim 11, wherein each electromagnetic radiation source emits electromagnetic radiation in an emission cone toward the substrate, and a portion of the electromagnetic radiation in the emission cone at a first angle is reflected from the substrate and then received by the pyrometer. 13. The method of claim 12, wherein the probe head of each electromagnetic radiation detector is curved to align with a conical surface of the emission cone and is configured to sample electromagnetic radiation in the emission cone at a second angle. 14. The method of claim 13, wherein electromagnetic radiation in the emission cone at the first angle has substantially the same intensity as electromagnetic radiation in the emission cone at the second angle. 15. The method of claim 14, further comprising the step of determining electromagnetic radiation emitted by the substrate by subtracting electromagnetic radiation reflected from the substrate from electromagnetic radiation received by the pyrometer. 16. The method of claim 15, further comprising the step of calculating the intensity of electromagnetic radiation emitted by the substrate by multiplying the intensity of the electromagnetic radiation sampled by each electromagnetic radiation source by the known reflectivity of the substrate, summing the results, and subtracting the sum from the intensity of the electromagnetic radiation received by the pyrometer. 17. The method of claim 16, wherein the reflectivity of the substrate is a ratio of the intensity of reflected electromagnetic radiation to the intensity of incident electromagnetic radiation. 18. The method of claim 16, wherein the reflectivity of the substrate is calculated by dividing the maximum intensity minus the minimum intensity of electromagnetic radiation emitted by an electromagnetic radiation source by the maximum intensity minus the minimum intensity of electromagnetic radiation emitted by the electromagnetic radiation source and reflected from a reflective plane. 19. The method of claim 10, further comprising the step of estimating the temperature of the substrate by applying Planck's law to the electromagnetic radiation emitted by the substrate. 20. An apparatus for estimating temperature, comprising: a plurality of electromagnetic radiation sources positioned to emit electromagnetic radiation toward the reflective plane, wherein each electromagnetic radiation source is configured to emit a cone of emitted electromagnetic radiation; a plurality of electromagnetic radiation detectors, each electromagnetic radiation detector comprising a probe head configured to receive electromagnetic radiation, the probe head being placed at a location between the electromagnetic radiation source and the reflecting plane in order to sample electromagnetic radiation emitted by a corresponding electromagnetic radiation source of the plurality of electromagnetic radiation sources; a pyrometer positioned to receive electromagnetic radiation originating from the plurality of electromagnetic radiation sources and reflected from the reflective plane; and A processor is configured to estimate temperature based on electromagnetic radiation received by the pyrometer and by the electromagnetic radiation detector.